Expression 6: "c" Subscript, "g" "r" "a" "d" "i" "e" "n" "t" , Baseline equals hsv left parenthesis, 50 times left bracket, 1...length left parenthesis, "I" , right parenthesis , right bracket , 1 , StartFraction, "e" left parenthesis, "I" left bracket, length left parenthesis, "I" , right parenthesis , right bracket minus "I" , right parenthesis Over "I" left bracket, length left parenthesis, "I" , right parenthesis , right bracket , EndFraction , right parenthesiscgradient=hsv50·1...lengthI,1,eIlengthI−IIlengthI